Gideon Mantell

Dinosaur Hunting

Rajasaurus narmadensis

When paleontologists Paul Sereno and Jeff Wilson arrived in India in 2001 to study a mixed collection of dinosaur
bones gathered by Indian scientists 18 years earlier, they found the bones spread
out on an office floor.

Sifting through the collection, they separated out the bones of a theropod, or meat-eating dinosaur. When they
found the center part of a skull, they recognized a horn resembling those of
dinosaurs found in Madagascar. Their search continued, yielding a left hip,
then a right hip, then a sacrum.

Sereno and Wilson consulted detailed, hand-drawn maps drafted by their Indian counterparts and discovered the bones
had been buried next to each other, as if they had been connected.

"There was a Eureka! moment when we realized we had a partial skeleton of an undiscovered species" said Sereno, a paleontology professor at the University of Chicago and a National Geographic Explorer-in-Residence.

The bones were collected in 1983
by Suresh Srivastava of the Geological Survey of India (GSI) and Ashok Sahni,
a paleontologist at Panjab University, during a search for dinosaur eggs and
nests.

Srivastava drew a detailed map
to document the position of the fossil bones as they lay in the field. The scientists
then stored the 65-million-year-old bones at a GSI office, where they stayed
until Sereno and Wilson arrived.

Working with Indian experts, Wilson
and Sereno reconstructed the skull of the new species, a stocky, 30-foot-long
(9-meter-long) carnivore named Rajasaurus narmadensis, which means "regal
dinosaur from the Narmada," the river region in western India where the
bones were found. The project was supported in part by the National Geographic
Society.

"We knew of fragments and
bones [in India]," said Sereno, who has discovered new dinosaur species
on five continents. "But this skull reconstruction offers the first glimpse
into the lost world of the Indian dinosaur."

There were already two Jurassic
dinosaur skeletons mounted in India. Neither, however, represents a single skeleton,
but is instead based on composites of isolated bones.

"We know that there were carnivorous
and herbivorous dinosaurs in India through individual bones, but we really don't
know just how they looked because no two bones can be reliably said to belong
to one individual," said Wilson, who is of the University of Michigan.
"Rajasaurus is important because it represents a partial skeleton and preserves
many details that clue us into its evolutionary relationships."

The reconstructed skull is missing
some parts, but it has the most important pieces: the jaws and the brain case.
Between 25 and 30 feet (7.6 and 9 meters) long, the Rajasaurus was heavy and
strong, and walked on two legs.

"There are several anatomical
details that make Rajasaurus a new species," said Wilson. "Perhaps
the most striking is the horn it bears on its head. The horn was probably rather
subtle. It may have been low and rounded."

The carnivorous Rajasaurus, which
lived in the Cretaceous Period at the end of the dinosaur age, preyed on long-necked
titanosaur sauropods, herbivorous dinosaurs that also roamed the Narmada region.
Bones from both dinosaurs were found together.

Indian paleontologists recently
found coprolites (fossilized dung) that provide additional clues to the diet
of those titanosaurs. >

"Large theropod eggs have
also been described by our group from the area where the skeleton of Rajasaurus
has been recovered, but it's difficult to relate the theropod eggs specifically
to Rajasaurus," said Sahni.

The scientists believe the Rajasaurus
is related to a family of large carnivorous dinosaurs, most of which had horns,
that roamed the southern hemisphere land masses of present Madagascar, Africa,
and South America.